Second-born kids more likely to become criminals, study finds

The “curse of the second-born” child might actually be true, a new study shows.

Second-born sons are more likely to be suspended from school, become juvenile delinquents and go to prison, according to a new study by MIT economist Joseph Doyle.

After poring through tons of data sets, Doyle and colleagues Sanni Breining, David Figlio, Krzys Karbownik and Jeffrey Roth found that second-born children, particularly sons, have a 25 percent to 40 percent increased likelihood of being troublemakers at school or with police when compared to first-born children in the same family.

The researchers came to this conclusion after examining thousands of family data sets of brothers from both Florida and Denmark, according to the report.

While researchers have previously suggested that first-born children have higher IQs, perform better in school and earn more money, this new report is among the first major studies to make a compelling case that second-born children are more at risk to become troublemakers.

Doyle said second-born sons could be more prone to trouble-making than older siblings because parents are often more invested in their first-born’s upbringing. Once a family’s second child arrives, parents tend to be less vigilant, he said.

“The firstborn has role models, who are adults. And the second, later-born children have role models who are slightly irrational 2-year-olds, you know, their older siblings,” Doyle told NPR. “Both the parental investments are different, and the sibling influences probably contribute to these differences we see in the labor market and what we find in delinquency. It’s just very difficult to separate those two things because they happen at the same time.”

According to the researchers, treating the second child differently from the first could have a long-term impact on their behavioral development.

Although not every family will have a troublemaker as their second child, the report suggests that keeping an eye on their children could be beneficial overall.